Arc-lamp.



N. A. HALBERTSMA.

ARC LAMP.

APPLICATION FILED APR. 18, l9l3.

Patented Dec. 12, 1916.

R 0 T N E V 1% WITNESSES UNITED STATES PATENT OFFICE.

NICOLAAS ADOLF HALBERTSMA, OF DARMS'IADT, GERMANY.

ARC-LAMP.

Application filed April 18, 1913.

To all whom it may concern Be it known that I, NICOLAAS ADoLr HAL- nnirrswm, electrical engineer, and a subject of the Queen of the Netherlands, and resident of Darmstadt, in the Grand Duchy of Hesse, Germany, with the ])0St0'l'fl0e address Riedlingerstrasse 20, have invented new and useful Improvements in or Relating to Arc Lamps, of which the following is a specification.

This invention relates to are lamps of the kind in which the arc is produced in a known manner by parallel carbon rods so that the arc in the burning away of the carbons is caused to move along that portion of the optical axis which forms the focus of the condenser and wherein by the production of shadows or other means the progress of the burning may be observed on the focusing line thereby dispensing with actual regulation of the are but solely maintaining its position within the focusing line. In these lamps horizontally arranged parallel carbons are used side by side, so that the crater produced in the burning assumes an oblique form, resulting in a more or less lateral distribution or radiation of the light.

According to the present invention the carbons are arranged parallel one above the other with the result that the positive face of the crater is located approximately symmetrically with regard to the axis of the optical system and the radiation upon the condenser therefore is uniform.

Figure 1 illustrates the effective quantity of light in the case of horizontal carbons which are located side by side. Fig. 2 shows the effective quantity of light in the case of carbons which. are vertically superposed, and placed in the optical axis. Fig. 3 is a lateral view of the carbons located above one another.

In the case of the horizontal carbons according to Fig. 1 the positive carbon burns away obliquely so that the theoretical curve of light distribution assumes a lateral po sition. Owing to the fact that a portion of the light is screened by the negative carbon, a practical light distributing curve 1 is obtained of which again only the efficient quantity of light 2 (indicated by the shaded portion) is actually effective for the lens 3 of the condenser. Now if the carbons are placed in vertical direction and parallel one above the other so that the positive carbon is Specification of'Letters Patent.

Patented Dec. 12, 1916.

Serial No. 761,912.

located above the negative carbon a light distributing curve 4 is obtained as shown in Fig. 2, which coincides with the theoretical distributing curve representing the maximum effect. In this instance, an effective quantity of light indicated by the shaded portion 5 is obtained which admits of the best and greatest illumination of the condenser lens 3 whereby a uniform illumination is attained at the same time.

In Fig. 3 the carbons are shown in lateral view with the positive carbon 6 located vertically above the negative carbon 7. The burning away takes place so that the crater S of the positive carbon is set back with regard to the crater of the negative carbon and maintains this relation during the burning. By this burning a crater is formed on the positive carbon symmetrically with regard to the central line of the optical system resulting in a light distributing curve according to Fig. 2.

Now what I claim and desire to secure by Letters Patent is the following:

1. In a continuous direct current are lamp, a projector, parallel carbons disposed within a vertical plane, the positive of said carbons being superposed in line with the optical axis of said projector and having its combustion end set back with reference to the corresponding end of the negative carbon whereby the positive crater burns substantially transverse and symmetrical relative to such optical axis.

2. In a direct current are lamp of the character described, a projector, parallel carbons disposed within a vertical plane and in line with the optical axis of the projector, the positive of said carbons having its crater set back with respect to the crater of the negative carbon whereby it burns sub stantially perpendicular to the optical axis solely by reason of the initial arrangement and continued maintenance of such relation ship.

3. A direct current projecting arc lamp comprising a projector, parallel carbons extending in the direction of the optical axis of such projector, the positive of said carbons being furthermore disposed above the other and'having its combustion end set back with regard to the corresponding end of the negative carbon whereby the positive crater maintains such relative location during the burning.

4. In a continuous direct current projecting arc lamp, a projector, parallel carbons arranged. along the optical axis of the projector and disposed in the same vertical plane the relative sizes and intervening space being so established that the crater of the positive carbon initially becomes set back relatively to the crater of the negative carbon whereby the projection of light is symmetrical relative to such optical axis.

5. In a direct current are lamp, a projec tor parallel carbons arranged along the optical axis of the projector, the positive of said carbons being superposed in the same vertical plane as the negative carbon, the relative sizes and intervening space being so established that the crater of the positive carbon becomes set back to a fixed extent relatively both to the crater of the negative carbon and to said projector whereby the projection of light is symmetrical relative to such optical axis.

In testimony, that I claim the foregoing as my invention, I have signed my name in presence of two Witnesses, this second day of April 1913.

NICOLAAS ADOLF HALBERTSMA.

lVitnesses JEAN G-RUND, CARL GRUND.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

